Poly microfibers

Fig. 8. Kinetics of liquid sorption in 10 replications using samples cut from the same composite sheet consisting of poly(Sty-co-DVB) microspheres (80% by weight) enmeshed in PTFE microfibers (similar size-distribution to that shown in Fig. 7)...

Fig. 21. A typical example of many time-studies of desorption from liquid saturated poly(Sty-co-DVB) particles enmeshed in PTFE microfibers. The Inset records the number, at> of residual sorbed molecules [in this case CHC13 in (Sty)98(DVB)2] per phenyl group of polymer over the first 10 min of desorption at 23 °C. The main plot records the logarithm of at over the first 70 min of the time-study. The breakpoints in the kinetics of desorption at aj, otg and ag mark sequentially the compositions at incipient elimination of molecules immobilized by adsorption, incipient transition from the rubbery state of the system to the glassy state, and finally completion of this transition as discussed in the text...

These studies of liquid sorption by poly(Sty-co-DVB) particles enmeshed in PTFE microfibers have shown that an adsorption parameter, a, characteristic of the molecular structure of a sorbed liquid with respect to that of the monomer unit in the polymer, can be determined with good precision (+1 in the third significant figure) by measuring the weight of sorbed liquid per unit weight of enmeshed particles. These adsorption parameters appear to be of fundamental scientific value and therefore potentially useful in understanding natural phenomena in which adsorption plays an important role. 

Pham QP, Sharma U, Mikos AG (2006) Electrospun poly(epsilon-caprolactone) microfiber and multilayer nanofiber/microfiber scaffolds characterization of scaffolds and measurement of cellular infiltration. Biomacromolecules 7(10) 2796-2805... 

Figure 17.2 SEM photomicrograph of polypropylene microfibers produced via extraction of an oriented poly(vinyl alcohol)/PP blend. Reproduced with permission from L. M. Robeson et al., J. Appl. Polym. Sci., 52, 1837 (1994).

Finally, signiflcant contrast increase of stained samples was reported when the HAADF-STEM technique was used for several systems, such as cellulose microfibers and whiskers within poly(lactic acid) [85],... 

Other methods are based on polymer blends of two immiscible polymers, a water-soluble matrix [e.g., poly(vinyl alcohol)] and an insoluble fiber-forming component [e.g., poly(ethylene terephthalate)]. Upon exfrusion, the streamlined flow characteristics produce a fibrillary morphology. The matrix is extracted after cold drawing. The resulting foamed slurry is then filtered off and spun into microfibers with a diameter of 0.1-10 pm. Using this method, ultrasuperfine fibers with counts of 10 " dtex are obtained for use as filter material [81]. 

Suzuki A, Tojyo M. Poly(ethylene-2,6-naphthalate) microfiber prepared by carbon dioxide laser-thinning method. Eur Polym J 2007 43(7) 2922-7. 

Strydom et al. [66] developed nanocoated cellulose used in the manufacture of tablets via direct compression. The research demonstrated that by coating cellulose microfibers with nanolayers of polyvinylpyrrolidone and poly(styrenesulfonate), the compaction properties of cellulose were dramatically improved without retarding the drug dissolution. Additional clear advantages were demonstrated, such as minimal weight gain of less than 1% as well as greater control over the surface properties of the fibers. 

Porcine skin Trypsin-EDTA+Triton X-100+deoxychoUc acid+peracetic NA Poly(ester uiethane)urea microfibers/digested extracellular matrix Hong et al. (2011)... 

To provide a prolonged and controlled drug release to the surface of wounds or bums, the material may contain two or more microfiber layers. Different layers may have different compositions. Each layer includes the biodegradable polymer with or without poly(N-vinyl)lactam. The layers may also have different biodegradable polymers (78). 

Bini, T.B., Gao, S, Wang, S., and Ramakrishna, S. (2006) Poly(l-lactide-co-glycolide) biodegradable microfibers and electrospun nanofibers for nerve tissue engineering an in vitro study. J. Mater. Sci., 41, 6453-6459. 

An electrical field in the form of an external stimulus offers numerous advantages (e.g., availability of equipment). This form of an external stimulus also allows for precise control over the magnitude of the current, the duration of electrical pulses, and the interval between pulses. Poly(vinyl alcohol) (PVA) is one of the well-known electroactive polymers with good thermal stability, chemical resistance, water permeability, and biocompatibility. Xia et al. demonstrated electric-field induced actuation of PVA microfibers (Fig. 5.4.5) [17]. 

Li Z M, Yang M B, Lu A, Feng J M and Huang R (2002) Tensile properties of poly(ethylene terephthalate) and polyethylene in-situ microfiber reinforced composite formed via slit die extrusion and hot stretching. Mater Lett 56 756-762. 

Li Z M, Li L B, Shen K Z, Yang M B and Huang R (2005) In situ poly(ethylene terephthalate) microfibers- and shear-induced non-iso thermal crystallization of isotactic polypropylene by online small angle X-ray scattering, Polymer 46 5358-5367. 

Li Z M, Xu X B, Lu A, Shen K Z, Huang R and Yang M B (2004) Carbon black/poly(ethylene terephthalate)/polyethylene composite with electrically conductive in situ microfiber network, Carhon 42 428-432. 

Li Z M, Yang M B, Yang W, Huang R and Feng J M (2002) Poly(ethyleneterephthalate)/poly-ethylene composite based on in situ microfiber formation, Polym Plast Technol Eng 41 19-32. 

Yesil S, Koysuren 0 and Bayram G (2010) Effect of microfiber reinforcement on the morphology, electrical, and mechanical properties of the polyethylene/poly(ethylene terephthalate)/carbon nanotube composites, Polym Eng Sci 50 2093-2105. 

Hurtado, A., Cregg, J.M., Wang, H.B., Wendell, D.F., Oudega, M., Gilbert, R.J., McDonald, J.W., 2011. Robust CNS regeneration after complete spinal cord transection using aligned poly-L-lactic acid microfibers. Biomaterials 32 (26), 6068—6079. 

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